Valid Arc Lost 2

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12 Sep 2020 07:57 #181844 by tommylight
Replied by tommylight on topic Valid Arc Lost 2

little_sparky wrote: ............... also checked my PSI into the machine and had more than enough, turned it down to about 100.

For normal plasma cutters that should be from 75 to 83 PSI, not 100, while the air is on and running out of the torch.
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12 Sep 2020 08:03 #181848 by little_sparky
Replied by little_sparky on topic Valid Arc Lost 2
I spoke to soon....

So I did about 5 x 50mm test cuts, no worries.

Went to cut some code and my very first pierce “valid arc lost”

So close.

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12 Sep 2020 08:13 #181849 by little_sparky
Replied by little_sparky on topic Valid Arc Lost 2
Okay an interesting finding,

I went back to the run tab and completed another 4 x 70mm cuts no worries

Then on the 5th one it pierced and started cutting, then after about 40mm it stopped and threw up the arc error again.

I’m not sure what this points to?

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12 Sep 2020 08:24 - 12 Sep 2020 08:25 #181851 by Aciera
Replied by Aciera on topic Valid Arc Lost 2
Likely not a debouncing issue.
All terminals are tight?
Faulty ArcOK circuit in the plasma?

Maybe I'll come up with some other ideas.

[edit]
No broken wires?
Last edit: 12 Sep 2020 08:25 by Aciera.
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12 Sep 2020 08:28 #181852 by rodw
Replied by rodw on topic Valid Arc Lost 2
It could point to there is more oxide to blow away yet.
It could also mean you are cutting too fast or too high... Try reducing your feed rate by 20%. Then try - 10%

I think Plasmac now has a setting that ignores ArcoK for cutting expanded metal. I would enable that and pause the cut if you don't cut right through.

My thinking is that if you are loosing and ArcOK because of an intermittent fault on a relay, it should cut fine without ArcOK becasue the plasma cutter is happy.

But before you do that, we need to eliminate cut height and cut speed as being the cause by trial and error.

Anyway, its great the resistors improved your results. You have to have a working circuit before debounce can help at all. I feel your pain as it brings back memories...
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12 Sep 2020 21:26 #181935 by tommylight
Replied by tommylight on topic Valid Arc Lost 2
Causes for lost arc while cutting, in this order:
1. power supply fluctuations, power cable to plasma to thin,
2. air pressure fluctuations, pressure to low, moisture in air supply
3. rusty ground clamp to table connection
4. debris/oil from compressor in air supply
Causes or lost arc at torch start, in this order:
1. No proper grounding and shielding of the electronics
2. air pressure to low or to high
3. power drop during arc transfer from thin cables or low current capability of the power grid/installation
4. charred nozzle/electrode from moisture/oil/debris in air supply.

Plasma cutters use a lot of power, cause a lot of interference, and are very picky about a lot of things. The only way to properly use them is to do test, more tests, and some more tests.
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16 Sep 2020 05:02 - 16 Sep 2020 05:03 #182353 by little_sparky
Replied by little_sparky on topic Valid Arc Lost 2
Okay so after taking in all the advice listed above, I think i'm almost there!

So working through tommy's list this is what I did.

Firstly, I turned down the amps on the everlast plasma cutter from 42 amps to 35 and slowed down my cut feedrate. I thought this might help with power fluctuations.

Secondly, I went out and got another good 2 stage air filter, giving me 4 in total now. I am also toying with the idea of adding my own homemade wall mounted desiccant filter, does anyone have any experience or recommendations with this?

Thirdly, I double checked every wire to see if there were any broken wires.

Next I played around with the cut speed and I ended up dropping it about 40% (seems large but I also dropped the amps too)

After all this, and Rod's new arc ok resistor resistor blowing away the built up oxide, I am getting reliable cuts with about 30 minutes of cut time not throwing up a single error yet.

Thanks for all your help guys and fingers crossed I dont have to reply to this topic again!
Last edit: 16 Sep 2020 05:03 by little_sparky.
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16 Sep 2020 06:57 #182390 by rodw
Replied by rodw on topic Valid Arc Lost 2
Great teamwork Sparky! Thanks for the update.

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